In boats and recreational vehicles it has long been desirable to provide a sewage holding tank which can be removed from the boat or RV to be pumped out, and replaced with another tank, or after emptying the original tank can be reinstalled. For example one such proposal for accomplishing this result is shown in U.S. Pat. No. 5,408,704. In such systems (or whenever a connection is provided between a conduit and a tank when the tank and conduit handle toxic or dangerous fluids), it is highly undesirable to have any leakage or dripping of liquids as the tank is being removed or reinstalled. This is especially important if--as has become desirable as shown by co-pending U.S. application Ser. No. 08/551,029 filed Oct. 31, 1995, now U.S. Pat. No. 5,681,148, issued Oct. 28, 1997, and Australian application serial no. 14895/97 filed Feb. 25, 1997, and U.S. application Ser. No. 08/839,267 filed Apr. 17, 1997 (atty. dkt. 19-125)--the holding tank also functions as a vacuum tank, operatively connected to a vacuum pump. In such situations a no drip, fluid (liquid and gas, e.g. vacuum) tight connection is particularly important. While a no drip, fluid tight, connection is important it must be able to be effected in a simple and quick manner.
According to the present invention a substantially no drip fluid (vacuum) tight connection between a conduit and a tank, and a tank assembly (particularly a combined sewage holding and vacuum tank assembly) for utilizing the connection, are provided. The invention is simple and easy to construct, install, and utilize, yet provides a substantially no drip and fluid tight connection making a replaceable combined sewage holding and vacuum tank very practical.
According to one aspect of the present invention a substantially no drip fluid tight connection between a conduit and a tank are provided comprising the following components: A first elongated hollow element having an end wall, a circumferential wall with inner and outer surfaces and a first opening extending through the circumferential wall between the inner and outer surfaces. An elongated first opening cover mounted in substantially fluid tight engagement with the outer surface of the first hollow element and reciprocal with respect to the first hollow element to move between a first position covering the first opening and substantially preventing fluid passage therethrough, and a second position at least partially uncovering the first opening to allow fluid passage therethrough. A second elongated hollow element having a circumferential wall with inner and outer surfaces. and a second opening extending through the circumferential wall between the inner and outer surfaces. An elongated second opening blocking element mounted in substantially fluid tight engagement with the inner surface of the second hollow element and reciprocal with respect to the second hollow element to move between a first position blocking the second opening and substantially preventing fluid passage therethrough, and a second position at least partially exposing the second opening to allow fluid passage therethrough, the blocking element having an end wall. And, biasing means for biasing the cover to the first position and the blocking element to the first position. One of the hollow elements is configured to be connected to a tank, and the other of the hollow elements is configured to be connected to a conduit.
The biasing means may comprise any conventional type of spring, compressible material, pneumatic elements, or the like, as long as they provide a predetermined desired force to bias one component to a particular position, and allow movement against the bias. For example the biasing means may comprise a first coil spring (metal or plastic) disposed over the hollow element outer surface and mounted between the cover and a first relatively stationary support, and a second coil spring disposed within the second hollow element and acting between the blocking element and a second relatively stationary support, the first hollow element may be connected to a conduit, and the second element to a tank. A holding element may be provided which releasably holds the cover and blocking element in the second positions thereof against the bias of the biasing means, so that fluid flows through the first and second hollow elements between the conduit and the tank.
The second hollow element may be mounted either exteriorly of the tank or within the tank. Preferably the first hollow element has substantially the same cross-sectional shape and dimensions as the blocking element and an initial positioning element is associated with each of the blocking element end wall and the first hollow element end wall so that when the first hollow element and the blocking element are moved into engagement with each other the positioning elements ensure proper relative positioning thereof. For example the positioning elements may comprise a single centrally located conical or hemispherical projection on the blocking element cooperating with a conical or hemispherical depression in the first element end wall, or vice versa.
The hollow elements may be tubular, having generally circular cross-sections, or may have polygonal cross-sections. The second tubular element can comprise a pair of annular ends with a tubular segment (e.g. of about 90-180.degree.) connected to the annular ends, with the segment having the second opening therein. The first hollow element may be operatively connected to a plurality of different types of conduits, which may be connected to a toilet, vacuum pump, vent, or other components.
According to another aspect of the present invention a combined sewage holding and vacuum tank assembly for a boat or recreational vehicle is provided. The assembly comprises the following components: A tank body having an inlet. A handle connected to the tank body to allow ready lifting, placement, and/or carrying of the tank body. A vacuum pump. A conduit for operatively connecting the inlet to the vacuum pump. And, means for providing a readily connectable and disconnectable substantially air and liquid tight connection between the conduit and the inlet. The tank may have rolling support elements, such as wheels, rollers, or casters.
The means for providing a substantially air and liquid tight connection between the conduit and the inlet may comprise any type of conventional bayonet or telescopic connection for such purposes, and is preferably substantially no drip. One preferred embodiment of such means comprises the following components: A first elongated hollow element having an end wall, a circumferential wall with inner and outer surfaces, and a first opening extending through the circumferential wall between the inner and outer surfaces. An elongated first opening cover mounted in substantially fluid tight engagement with the outer surface of the first hollow element and reciprocal with respect to the first hollow element to move between a first position covering the first opening and substantially preventing fluid passage therethrough, and a second position at least partially uncovering the first opening to allow fluid passage therethrough. A second elongated hollow element having a wall with inner and outer surfaces, and a second opening extending through the wall between the inner and outer surfaces. And, an elongated second opening blocking element mounted in substantially fluid tight engagement with the inner surface of the second hollow element and reciprocal with respect to the second hollow element to move between a first position blocking the second opening and substantially preventing fluid passage therethrough, and a second position at least partially exposing the second opening to allow fluid passage therethrough, the blocking element having an end wall. One of the hollow elements is connected to the tank, and the other of the hollow elements is connected to the conduit.
The details of the air and liquid tight connection may be specifically as described above.
It is the primary object of the present invention to provide a simple to make, use and install--yet highly effective--substantially no drip fluid tight connection between a conduit and a tank, and a combined sewage holding and vacuum tank assembly for a boat or recreational vehicle containing such a connection. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.